Support Support Downloads Knowledge Base Case Manager My Juniper Community

Knowledge Base

Search our Knowledge Base sites to find answers to your questions.

Ask All Knowledge Base Sites All Knowledge Base Sites JunosE Defect (KA)Knowledge BaseSecurity AdvisoriesTechnical BulletinsTechnotes Sign in to display secure content and recently viewed articles

[##DELETE##] [CX] Minimum 3G/4G Broadband Connection Signal Values for CX111



Article ID: KB27728 KB Last Updated: 11 Jan 2020Version: 2.0

3G and 4G connections are highly dependent on signal strength and signal quality.  This article provides recommended values for broadband connectivity.


CX111 supports both 3G and 4G modems. The signal strength and signal quality both contribute to performance and in extreme cases, connectivity.


Signal strength and signal quality can affect data performance and basic connectivity.  This article breaks down each, and also provides recommended values for broadband connectivity.


Signal Strength

  • Influences connection to the cellular tower
  • Represented by RSSI, which is measured in dBm
  • RSSI is a negative value, and the closer to 0, the stronger the signal

NOTE: Signal Strength must be reviewed by the numeric values, ie. -dBm. The number of signal bars displayed by devices may give inaccurate perception of actual signal strength.


Signal Quality

  • Influences data throughput speeds on mobile broadband networks
  • Represented by signal noise ratios, measured in dBm
  • Noise ratio representation varies by mobile broadband technology:
    • LTE - SINR
      • SINR is a positive dBm value
      • Higher SINR numbers = better quality connection
    • WiMAX - CINR
      • CINR is a positive dBm value.
      • Higher CINR numbers = better quality connection
      • EC/IO is a negative dBm value. Values closer to 0 are stronger signals.
      • Lower EC/IO ‘numbers’ = better quality connection

Minimum Signal Values

  Signal Strength Signal Quality
Technology Most Modems
(RSSI or bars)
Minimum Signal Values dBm > -85 dBm > -64 dBm > 7 dBm > 9 dBm > -10
  • Exceptions apply to the following modems in LTE mode: Pantech UML 290, Novatel 551L
  • LG VL600 does not report db values, only bars.  LG VL600 requires a minimum of 2 bars.


  1. Both Signal Strength and Signal Quality must be considered for successful cellular data connection.
  2. Measured or reported values vary by modem, carrier, and network environment.
  3. There is no black/white answer to what constitutes a successful connection.
  4. Although signal strength may appear to be adequate, throughput speeds may vary due to dependencies on cellular tower loads.

Comment on this article > Affected Products Browse the Knowledge Base for more articles related to these product categories. Select a category to begin.

Getting Up and Running with Junos

Getting Up and Running with Junos Security Alerts and Vulnerabilities Product Alerts and Software Release Notices Problem Report (PR) Search Tool EOL Notices and Bulletins JTAC User Guide Customer Care User Guide Pathfinder SRX High Availability Configurator SRX VPN Configurator Training Courses and Videos End User Licence Agreement Global Search